title: Complexes assembled from TMV-derived spherical particles and entire virions of heterogeneous nature.
abstract: Previously, we described some structural features of spherical particles (SPs) generated by thermal remodelling of the tobacco mosaic virus. The SPs represent a universal platform that could bind various proteins. Here, we report that entire isometric virions of heterogeneous nature bind non-specifically to the SPs. Formaldehyde (FA) was used for covalent binding of a virus to the SPs surface for stabilizing the SP-virus complexes. Transmission and high resolution scanning electron microscopy showed that the SPs surface was covered with virus particles. The architecture of SP-virion complexes was examined by immunologic methods. Mean diameters of SPs and SP-human enterovirus C and SP-cauliflower mosaic virus (CaMV) compositions were determined by nanoparticle tracking analysis (NTA) in liquid. Significantly, neither free SPs nor individual virions were detected by NTA in either FA-crosslinked or FA-untreated compositions. Entirely, all virions were bound to the SPs surface and the SP sites within the SP-CaMV complexes were inaccessible for anti-SP antibodies. Likewise, the SPs immunogenicity within the FA-treated SPs-CaMV compositions was negligible. Apparently, the SP antigenic sites were hidden and masked by virions within the compositions. Previously, we reported that the SPs exhibited adjuvant activity when foreign proteins/epitopes were mixed with or crosslinked to SPs. We found that immunogenicity of entire CaMV crosslinked to SP was rather low which could be due to the above-mentioned masking of the SPs booster. Contrastingly, immunogenicity of the FA-untreated compositions increased significantly, presumably, due to partial release of virions and unmasking of some SPs-buster sites after animals immunization.
authors.affiliation: a Department of Virology , Lomonosov Moscow State University , 1/12 Leninskie gory, Moscow 119991 , Russia .
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Trifonova
authors.forename: Nikolai
authors.initials: N
authors.lastname: Nikitin
authors.forename: Anatoly
authors.initials: A
authors.lastname: Gmyl
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Lazareva
authors.forename: Olga
authors.initials: O
authors.lastname: Karpova
authors.forename: Joseph
authors.initials: J
authors.lastname: Atabekov
mesh_terms: D000956:Antigens, Viral / Q000276:immunology; D017795:Bromovirus / Q000276:immunology / Q000502:physiology; D017796:Caulimovirus / Q000276:immunology / Q000502:physiology*; D004686:Encephalomyocarditis virus / Q000276:immunology / Q000502:physiology; D030015:Enterovirus C, Human / Q000276:immunology / Q000502:physiology; D000939:Epitopes; D014027:Tobacco Mosaic Virus / Q000276:immunology / Q000502:physiology*; D014771:Virion / Q000276:immunology / Q000502:physiology*
chemical_list: D000956:Antigens, Viral; D000939:Epitopes
keywords: immunogenic compositions; isometric viruses; platforms; spherical particles; tobacco mosaic virus